What Are The Risk Factors For Age-Related Macular Degeneration?

The most important risk factor for age-related macular degeneration is age. Although macular degeneration can occur in patients younger than 50 years of age, it is uncommon. Numerous studies show that people over the age of 60 years are at greatest risk for development of macular degeneration. The risk continues to increase the older a person is, and studies have shown that it may be as high as 30% in those 75 years of age and older. Smoking is another consistent risk factor associated with the development of macular degeneration.

Current smokers have a two- to fourfold greater risk of developing the later stages of macular degeneration than non-smokers. Even after quitting, an increased risk persists for as long as 15 years—or even longer. However, the risk decreases with cessation of tobacco use. This decreased risk is even apparent in the first year of stop-ping. Smoking not only increases the risk of macular degeneration, but current or recent smokers cannot take the recommended vitamin supplement for macular degeneration prevention because beta-carotene, one of the vitamins in these supplements, increases the risk of lung cancer in smokers. Family history is another strong risk factor.

Patients with a first-degree relative who has macular degeneration have a two- to threefold greater risk of developing the disease than patients without first-degree relatives with macular degeneration. In addition to family history, tremendous work with regard to macular degeneration and genetics has revealed that certain genes are strongly associated with macular degeneration. Patients who have particular variants of this gene have a much greater risk of developing the dis-ease. One such variant involves the complement factor H gene, or CFH gene. The presence of this variant may account for almost 50% of all cases in the United States.

Other risk factors include race (Whites are more likely to lose vision from macular degeneration than African Americans), gender (women appear to be at greater risk than men), and obesity. Studies typically include these three factors as reasonably well-accepted causes associated with macular degeneration. Other characteristics, such as farsightedness, light iris color, sun-light exposure, and hypertension have been associated with macular degeneration in some studies, classifying these characteristics as possible risk factors. While any form of hypertension may be associated with increased risk of developing macular degeneration, uncontrolled hypertension (defined as blood pressure greater than 160/95 mm Hg) is associated with more of a risk.